With a high regard for sealing properties, elastic bodies (e.g. rubber) are used for parts that slide while maintaining the sealing performance, e.g., a gasket which is integrated with a plunger of a syringe and forms a seal between the plunger and the barrel. Such elastic bodies, however, have a slight problem in their sliding properties (see Patent Literature 1). Thus, a sliding property improving agent (e.g. silicone oil) is applied to the sliding surface. It is, however, pointed out that silicone oil can accelerate adsorption and aggregation of proteins in recently marketed bio-preparations. Meanwhile, gaskets which are not coated with a sliding property improving agent have poor sliding properties, and thus do not allow plungers to be smoothly pushed but cause them to pulsate during administration. Hence, some problems occur such as an inaccurate injection amount and infliction of pain on patients.
A technique of coating with a self-lubricating PTFE film (see Patent Literature 2) is known to simultaneously satisfy such conflicting requirements, that is, the sealing properties and the sliding properties. The film, however, is generally expensive and thus increases the production cost of processed products, limiting its application range. Moreover, reliability concerns exist with the use of PTFE film coated products in applications where durability against repeated sliding motion is required. Another problem is that as PTFE is vulnerable to radiation, PTFE coated products cannot be sterilized by radiation.
Furthermore, the use in other applications where sliding properties in the presence of water are required can be considered. Specifically, water can be delivered without a loss by reducing the fluid resistance of the inner surface of a pre-filled syringe or the inner surface of a pipe or tube for delivering water, or by increasing or greatly reducing the contact angle with water. Another example is catheters which are inserted into blood vessels or urethras and are thus required to have high sliding properties so as to avoid hurting blood vessels or urethras and also avoid causing pain to patients. Moreover, drainage of water on wet roads and of snow on snowy roads can be improved by reducing the fluid resistance of the groove surfaces of tires, or by increasing or greatly reducing the contact angle with water. This leads to improved hydroplaning performance and enhanced grip performance, and therefore better safety. In addition, less adhesion of wastes and dusts can be expected when the sliding resistance of the sidewall surfaces of tires or walls of buildings is reduced, or when their contact angle with water is increased.
Further advantageous effects can be expected, such as: less pressure loss when water, an aqueous solution or the like is delivered through a diaphragm such as a diaphragm pump or valve; easy sliding of skis or snowboards, achieved by enhancing the sliding properties of the sliding surfaces thereof; better noticeability of road signs or signboards, achieved by enhancing the sliding properties thereof to allow snow to slide easily on the surface; reduction in water resistance or drag and in protein adsorption on the outer peripheries of ships, and therefore less adhesion of bacteria on the outer peripheries, achieved by reducing the sliding resistance of the outer peripheries or by increasing the contact angle with water; and reduction in water resistance or drag of swimsuits, achieved by improving the sliding properties of the thread surfaces thereof.